The present invention relates to labelling apparatus for applying labels to the outer surface of a container or article to be labelled. In particular, the invention is related to a method and apparatus of cutting a label from a roll-fed supply, applying adhesive to or activating adhesive on the rear face of the labels and moving the labels in time synchronization with an article to be labelled.
In the past, a number of different labelling apparatus have been proposed for applying labels to containers or the like by adhering the label to the container and subsequently wrapping the label around the container by rolling the container along a fixed surface. In particular, prior art labellers have been designed for pressure sensitive adhesive labels carried on a backer strip with the backer strip being removed from the labels as the labels are advanced in time synchronization with a container. It is desirable to have a machine capable of withdrawing a label from a roll label supply and apply an adhesive to or activating an adhesive on the back face of the label as necessary for application to a container. Labels which require application of an adhesive are less expensive and have particular application for the new type of plastic containers which are more readily deformable. With containers of this type, an adhesive is often applied to the leading edge and trailing edge of the label with the portion of the label being unsecured.
One such prior art machine is disclosed in U.S. Pat. No. 4,323,416. In this case, the strip of labels is advanced from a roll supply and passed through a cutting mechanism for subsequent engagement by a vacuum drum. The drum in combination with belts moving over the surface thereof, advance the label to the labelling point in time synchronization with an article to be labelled. Adhesive is applied to the rear face of the label as the label is moved past a gluing station.
One of the problems with prior art labellers adapted to applied adhesive to the rear face of a label, prior to or after cutting from a roll label supply, is that it is difficult to apply the adhesive to the label in a controlled manner whereby the conveyor means for advancing the label is not immediately contaminated. This problem is compounded by the speed of movement of the labels to the labelling location.
According to the present invention, a roll-feed labeller is possible which intermittently advances labels to be applied to containers and applies adhesive to at least the leading edge of the label as it is held stationary with respect to a moving conveyor. The adhesive is applied to the first label of a series of roll-feed labels, as it is attached to the series which are engaged upstream of a cutting mechanism. The labels are cut from the label supply in time synchronization with the advance of a container to be labelled to cause the leading edge of a label to meet with a surface of the container to be labelled as they are both advanced past a labelling location. The container advances past the labelling location in a manner to apply the remaining portion of the label to the surface of the container. The method of this apparatus is also part of the present invention.
The invention is also directed to the method and apparatus for applying adhesive to at least the leading edge of the first to be applied label as it is held stationary with respect to a moving conveyor means.
The apparatus and method for synchronizing roll fed labels with an article to be labelled can advantageously be used with labels which have a heat sensitive adhesive previously applied which is heated as the label is held stationary on the conveyor or a label supply which has a solvent reactivated adhesive which is reactivated as the label to be applied is on the conveyor.